Investigation of CO2 Adsorption on Avocado Stone-Derived Activated Carbon Obtained through NaOH Treatment

Activated carbons were prepared from avocado stone through NaOH activation and subsequent carbonization. The following textural parameters were achieved: specific surface area: 817-1172 m(2)/g, total pore volume: 0.538-0.691 cm(3)/g, micropore volume 0.259-0.375 cm(3)/g. The well-developed microporosity resulted in a good CO2 adsorption value of 5.9 mmol/g at a temperature of 0 & DEG;C and 1 bar and selectivity over nitrogen for flue gas simulation. The activated carbons were investigated using nitrogen sorption at -196 & DEG;C, CO2 sorption, X-ray diffraction, and SEM. It was found that the adsorption data were more in line with the Sips model. The isosteric heat of adsorption for the best sorbent was calculated. It was found that the isosteric heat of adsorption changed in the range of 25 to 40 kJ/mol depending on the surface coverage. The novelty of the work is the production of highly microporous activated carbons from avocado stones with high CO2 adsorption. Before now, the activation of avocado stones using NaOH had never been described.

Automated summary

Activated carbons with highly microporous structure were successfully prepared from avocado stones through NaOH activation and subsequent carbonization. The obtained activated carbons showed specific surface areas in the range of 817-1172 m²/g, total pore volumes of 0.538-0.691 cm³/g, and micropore volumes of 0.259-0.375 cm³/g. These activated carbons exhibited excellent CO2 adsorption capacity of 5.9 mmol/g at 0℃ and 1 bar, as well as selectivity over nitrogen for flue gas simulation. The novelty of this work lies in the production of high-performance activated carbons from avocado stones using NaOH activation, which has not been reported before.